Avoid a null pointer dereference on clean-up after oom in ac3 encoder.
Merge remote-tracking branch 'cehoyos/master'

* cehoyos/master:
  Avoid a null pointer dereference on clean-up after oom in ac3 encoder.

Merged-by: Michael Niedermayer <michaelni@gmx.at>
update all trac links to use the trac subdomain

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>